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Biomedical subjects

P Schachern

Publications and source records attributed to P Schachern.

5 recordsLinked to original sources

Paediatric otoscopy--clinical and histological correlation.

Otoscopy is a subjective clinical method. Its subjectively has led physicians to verify its accuracy through correlations with findings of otomicroscopy, pneumatic otoscopy, tympanometry, and myringotomy. In the very young population, however, the interpretation of otoscopic findings become more difficult. To improve the interpretation of normal otoscopy in young children, an otoscopic-histological correlation was attempted in children up to nine years of age. Twenty-one temporal bones from 15 children aged from two days to nine years who had no evidence of otological disease or congenital anomalies were examined under light microscopy; the thickness of the pars flaccida, posterior superior quadrant, and umbo were measured. Twenty-five eardrums of 15 healthy children without past or present history of otological disease were examined using otoscopy; a photograph of each eardrum was obtained. Our study demonstrates that structural changes in the tympanic membrane during these years of childhood have a good correlation with otoscopic findings. Understanding normal histological changes in the paediatric eardrum may improve our interpretation of otoscopic findings.

Aging

Pathology of labyrinthine ossification.

Ossification of the inner ear is the result of multifactorial pathogeneses, such as infection or malignant infiltration, and otosclerosis. Ossification of the inner ear spaces is a well documented sequela of suppurative labyrinthitis. In this study of human temporal bones, sections from 14 patients (28 temporal bones) were studied. In addition to the osseous tissue within the inner ear, findings included neoplasms, otosclerosis, otitis media, trauma, and Fabry's disease. We have attempted to correlate these conditions and their influence on the formation of osseous tissue within the spaces of the inner ear. Tympanogenic infection and vascular compromise were found to play an important role in ossification. The scala tympani of the basal turn of the cochlea was frequently the site involved.

Adult

A histopathological study of the relationship between otitis media and mastoiditis.

From a total of 1408 human temporal bones, 229 with otitis media or mastoiditis were selected; other contributing diseases were excluded. Of this group, 19.2% had an obstruction of the aditus ad antrum with pathologic tissue, usually granulation tissue. Although pathologic fluid and tissue were usually distributed throughout the middle ear and mastoid, in some cases, the most severe conditions were restricted to the mastoid. Pathologic conditions were more severe in cases with obstruction. An interesting observation was that columnar epithelial cells, goblet cells, and mucoid effusion were not observed in the mastoid, suggesting a restriction of secretory cells to the middle ear proper. It appears that obstruction of the aditus ad antrum contributes to the pathogenesis and accentuates pathologic conditions in otitis media.

Granulation Tissue

Permeability of the human round-window membrane to cationic ferritin.

An ultrastructural study was done in three sequential steps to determine if the human round-window membrane was permeable to macromolecules. Cationic ferritin was first placed for one hour in the round-window niche of two live rhesus monkeys. The same tracer was then placed in the same manner in two rhesus monkeys that had been dead for one hour. In both groups, cationic ferritin was observed to traverse the round-window membrane through pinocytotic vesicles into the scala tympani. After establishing that the transport capabilities of the round-window membrane of the monkey remained present one hour after death, cationic ferritin was placed for one hour in the round-window niche of two humans who had been dead for 30 minutes and one hour. The tracer was observed to traverse the round-window membrane through pinocytotic vesicles into the scala tympani in both humans. This report may be the first to document morphologically the permeability of human round-window membranes to macromolecules.

Animals

Experimental studies on round window structure: function and permeability.

Current research and an overall review of 12 years of round window membrane studies is presented. The approach, rationale, and concepts that have evolved from the studies are described. An ultrastructural study of the round window membrane of rhesus monkeys disclosed three basic layers: an outer epithelium, a middle core of connective tissue, and an inner epithelium. Morphologic evidence in monkeys, cats, and chinchillas suggests that these layers of the round window participate in absorption and secretion of substances to and from the inner ear, and that the entire membrane could play a role in the defense system of the ear. Cationic ferritin, horseradish peroxidase, 1-micron latex spheres, and neomycin-gold spheres placed in the middle ear of these experimental animals were observed to traverse the round window membrane through pinocytotic vesicles. Three-micron latex spheres and anionic ferritin were not incorporated by the membrane. Cationic ferritin and 1-micron latex spheres placed in perilymph were incorporated by the inner epithelial cells, suggesting absorptive capabilities of the round window membrane. Cationic ferritin was observed within the mesothelial cells underlying the scala tympani side of the basilar membrane, suggesting a role for these cells in the inner-ear defense system. A review of the subject and a general perspective from the author's viewpoint are discussed.

Animals